RE: Problem Dynamically Building Query String In XSLT

Given the limitations of 1.0, where you can't manipulate sequences of
strings, or create and then process temporary trees, I would do:

<xsl:variable name="u">
  <xsl:text>pagename.aspx?</xsl:text>
  <xsl:if test="$varTarget">
    <xsl:text>target=</xsl:text>
    <xsl:value-of select="$varTarget">
    <xsl:text>&amp;</xsl:text>
  </xsl:if>
  <xsl:if test="$varPage">
    <xsl:text>page=</xsl:text>
    <xsl:value-of select="$varPage">
    <xsl:text>&amp;</xsl:text>
  </xsl:if>
  .. repeat for other parameters
</xsl:variable>
<xsl:value-of select="substring($u, 1, string-length($u - 1))"/>

that is, add an & after every parameter, then at the end strip off the last
character of the string.

Michael Kay
http://www.saxonica.com/


> -----Original Message-----
> From: Trish@xxxxxxxxxxxxxx [mailto:Trish@xxxxxxxxxxxxxx] 
> Sent: 31 July 2007 17:25
> To: xsl-list@xxxxxxxxxxxxxxxxxxxxxx
> Subject:  Problem Dynamically Building Query String In XSLT 1.0
> 
> Hi:
> 
> I need to construct a query string of an unknown number of 
> parts. I have to use XSLT 1.0. We are also purposefully not 
> using any asp in the template, so I have to rely on XSLT 1.0 
> functionality alone.
> 
> My problem is detecting whether or not the element I'm adding 
> to the query string is the first element and therefore 
> requires a "?" in front of it or whether I should use "&amp;" instead.
> 
> For instance, here's a possible URL that I want to build:
> 
> pagename.aspx?page=2&sort=default&target=newpagename.aspx
> 
> When I'm building the string, none or part or all of the 
> possible query string elements may be present. In the 
> interest of keeping the query string as short as possible, I 
> don't want to show any of the elements that don't have values 
> (aye, there's the rub). I also don't want to have one of the 
> elements always present so it is always first and eliminates 
> the problem of whether to add the &amp; or the ?.
> 
> My attempts so far have been REALLY ugly as they are 
> repetitious and code heavy, as you'll see below, as well as 
> totally unsuccessful. Has anyone else come up with a better 
> way to do this?
> 
> Here's my last desperate attempt (the variable names used are 
> the possible values for the query string elements and are 
> defined elsewhere). I was trying to change the value of 
> $paramQueryMark by submitting as a parameter to queryMark, 
> but the value of the parameter is lost when I go back to queryBuilder:
> 
> <xsl:value-of select="$varPage" />
> <xsl:call-template name="queryBuilder" />
> 
> <xsl:template name="queryBuilder">
> 	<xsl:param name="paramQueryMark" select="'false'" />
> 	<xsl:if test="string($varTarget) or 
> string($varPageNumber) or string($varSortSelected)">
> 		<xsl:text>?</xsl:text>
> 	</xsl:if>
> 	<xsl:if test="string($varTarget)">
> 		<xsl:if test="$paramQueryMark = 'true'">
> 			<xsl:text>&amp;</xsl:text>
> 		</xsl:if>
> 		target=<xsl:value-of select="$varTarget" />
> 		<xsl:call-template name="queryMark">
> 			<xsl:with-param name="paramQueryMark"
> select="'true'" />
> 		</xsl:call-template>d
> 	</xsl:if>
> 	<xsl:if test="string($varPageNumber) and $varPageNumber != '1'">
> 		<xsl:if test="$paramQueryMark = 'true'">
> 			<xsl:text>&amp;</xsl:text>
> 		</xsl:if>
> 		page=<xsl:value-of select="$varPageNumber" />
> 		<xsl:call-template name="queryMark">
> 			<xsl:with-param name="paramQueryMark"
> select="'true'" />
> 		</xsl:call-template>
> 	</xsl:if>
> 	<xsl:if test="string($varSortSelected)">
> 		<xsl:if test="$paramQueryMark = 'true'">
> 			<xsl:text>&amp;</xsl:text>
> 		</xsl:if>
> 		sort=<xsl:value-of select="$varSortSelected" />
> 		<xsl:call-template name="queryMark">
> 			<xsl:with-param name="paramQueryMark"
> select="'true'" />
> 		</xsl:call-template>
> 	</xsl:if>
> </xsl:template>
> 
> <xsl:template name="queryMark">
> 	<xsl:param name="paramQueryMark" />
> </xsl:template>
> </xsl:stylesheet>
> 
> Thanks for your help!
> Trish